1. Field of the Invention
This invention relates to a sewing station having a preclamp, and more particularly, to a sewing station having a preclamp which facilitates transfer of bulky workpieces from a loading location to a sewing location within the sewing station.
2. Description of Related Art
In the sewing industry, it is typical for a sewing operation to require that an operator place a workpiece, for example two pieces of cloth to be sewn together, underneath a sewing head where the workpiece is then clamped to a cloth plate such that the operator may then remove his hands and the cloth plate and clamp are then driven in a predetermined pattern under the sewing head to cause the workpiece to be sewn. In order to facilitate loading and placement of the workpiece underneath the sewing head, the workpiece may be first loaded and manually clamped to a pallet which is subsequently coupled to a drive mechanism at the sewing head where a sewing operation is performed on the workpiece.
The use of a pallet to load workpieces into a sewing station has typically been limited to use with workpieces which have dimensions on the same order as the size of the pallet and which are capable of lying relatively flat on the pallet such that the pallet may be easily picked up or otherwise moved to the sewing station. Mounting of oversized workpieces on the pallet may result in the workpiece interfering with efficient coupling of the pallet to the drive mechanism for the sewing operation and further may interfere with handling or movement of the pallet from a loading location to the sewing station. In addition, clamping structures commonly used with known pallets are generally unsatisfactory for operating on large, unwieldy or bulky workpieces.
Thus, when a large or bulky workpiece is to be sewn, it is necessary for an operator to manually place the unwieldy or bulky workpiece directly underneath the sewing head where the workpiece is then clamped to a cloth plate for manipulation by a drive mechanism during the sewing operation. It should be therefore apparent that it is necessary to forego the advantages provided by a pallet system when a large or bulky workpiece is to be operated upon such that the inefficiencies associated with manually placing a workpiece directly in the sewing station are compounded as the access room underneath the sewing head is limited.
An example of a workpiece having a bulky construction which must be manually placed directly underneath the sewing head prior to the sewing operation is an automobile air bag having a substantially circular configuration wherein the end of straps used for limiting the inflation of the bladder portion of the bag must be sewn to an exterior surface of the bag. A workpiece having this bulky construction cannot be easily loaded to any known pallet, nor can such a workpiece be conveniently held in an assembled condition prior to placement under the sewing head.